<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .nav{
            width: 100%;
            height: 20px;
            background-color: #ccc;
        }
        .popup{
            width: 300px;
            height: 300px;
            border: 1px solid red;
            position: absolute;
            left: 50%;
            top: 50%;
            margin-left: -150px;
            margin-top: -150px;
        }
        .popup .title{
            height: 20px;
            width: 100%;
            background: deeppink;
            cursor: move;
        }
    </style>    
</head>
<body>
    <div class="nav">注册信息</div>
    <div class="popup" id="popupfather">
        <div class="title" id="popupson">我是窗口标题，可拖着我走</div>
        <div class="content">我是窗口内容</div>
    </div>
    <script>    
        var popupfather = document.getElementById('popupfather');
        var popupson = document.getElementById('popupson');

        popupson.onmousedown = function(event){
            var event = event || window.event;
            var that = this;
            var x = event.clientX - popupfather.offsetLeft - 150; //当前鼠标点击处相对于popupfather所在位置x ， -150 是处理margin值
            var y = event.clientY - popupfather.offsetTop - 150; //当前鼠标点击处相对于popupfather所在位置y
            document.onmousemove = function(event){
                var event = event || window.event;
                popupfather.style.left = event.clientX - x + "px";
                popupfather.style.top = event.clientY- y + "px";
                window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();

            }
        }
        document.onmouseup = function(){
            document.onmousemove = null;
        }
    </script>
</body>
</html> 
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版权声明：本文为CSDN博主「秋天1014童话」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/u013217071/article/details/53572540